Google will no longer trust SSL/TLS certificate authorities WoSign and its subsidiary StartCom with the launch of Chrome 61 for not maintaining the certificates. The move came after Google was notified by GitHub’s security team on August 17, 2016, that Chinese Certificate Authority WoSign had issued a base certificate for one of GitHub’s domains to an unnamed GitHub user without authorization. Google conducted an investigation in public as a collaboration with Mozilla and the security community, which uncovered several other cases of WoSign misissuance of certificates.
Source: https://thehackernews.com/2017/07/chrome-certificate-authority.html